Liquid crystal display panel and related device for receiving a touch command

ABSTRACT

A liquid crystal display panel includes a first substrate, a second substrate, a first electrode, a second electrode, a third electrode, an isolating layer, and a conductor. The first electrode is disposed between the first substrate and the isolating layer, on which the conductor is disposed. Each of the second and third electrodes is disposed on the second substrate and includes a contact surface. The second and third electrodes are not in contact with each other and are separated by a gap. The conductor is disposed in accordance with the location of the gap.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a liquid crystal display device, andmore particularly to a liquid crystal display device capable ofreceiving touch commands.

2. Description of the Prior Art

With rapid development in technology, massive amount of data can betransmitted, processed and stored in digital formats. Electronic devicescapable of accessing digital data have thus become important tools inmodern society. Notebook computers, mobile phones, and personal digitalassistants (PDAs) are light and easy-to-carry portable electronicdevices that allow users to search, read and store different types ofdigital data. Since portable electronic devices aim at light weight andthin appearance, there is usually insufficient space for traditionalinput devices such as keyboard or mouse. Instead, touch panels arecommonly used for portable electronic devices as the human-machineinterface for data transmission. When a user enters a touch command bypressing a touch panel, the touch panel can detect the location of theapplied pressure (or the amount of the applied pressure) and control theoperation of the portable device accordingly.

Liquid crystal display (LCD) panels are commonly used for displayscreens in portable electronic devices. Based on how input commands areidentified, touch panels can be categorized into four major types:resistive, capacitive, surface wave and optical touch panels. Referenceis made to FIG. 1 for a diagram of a prior art LCD device 10. The LCDdevice 10 includes an LCD panel 110 and a resistive touch panel 120. Theresistive touch panel 120 and the LCD panel 110 are connected via anadhesion glue film 140. The LCD panel 110 includes a first substrate112, a first electrode 114, a liquid crystal layer 115, a secondelectrode 116, and a second substrate 118. The resistive touch panel 120includes a substrate 122, a lower transparent conducting film 124, aplurality of dot spacers 125, an upper transparent conducting film 126,a connecting layer 127, a polyethylene terephthalate (PET) layer 128,and a trace 130. The connecting layer 127 is disposed between the uppertransparent conducting film 126 and the lower transparent conductingfilm 124, and the dot spacers 125 are disposed in a matrix manner withinthe space between the upper transparent conducting film 126 and thelower transparent conducting film 124. When a user applies a pressure onthe PET layer 128 using a finger, a pen or other input devices, theupper transparent conducting film 126 and the lower transparentconducting film 124 will make contact with each other at the exact pointof the applied pressure, thereby generating a corresponding voltage. Thevoltage is then transmitted to a central processor (not shown in FIG. 1)via the trace 130 for identifying the touch command entered by the user.Since the resistive touch panel 120 and the LCD panel 110 are connectedvia the adhesion glue film 140, the prior art LCD device 10 requiredmany stacks of different layers, resulting in higher manufacturingcosts, larger size and heavier weight. Optical performances such asbrightness or contrast of the prior art LCD device 10 will also beinfluenced.

Reference is made to FIG. 2 for a diagram of an LCD device 20 disclosedin U.S. Patent Publication No. US2006/0017710. The LCD device 20includes a plurality of data lines, a plurality of gate lines, aplurality of sensor signal lines, and a plurality of pixels. For ease ofexplanation, only a data line DL, a gate line GL, sensor signal linesPj, Si, Psd, and a pixel PX are illustrated in FIG. 2. The pixel PXincludes a display unit DC and a detecting unit DC. The display unit DC,coupled to the data line DL and the gate line GL, includes a thin filmtransistor (TFT) switch TFT1, a liquid crystal capacitor C_(LC) and astorage capacitor C_(ST). The detecting unit SC, coupled to the sensorsignal lines Pj, Si and Psd, includes a thin film transistor switchTFT2, a thin film transistor switch TFT3, and a variable capacitorC_(V). In the LCD device 20, when a user enters a touch command, theapplied force changes the capacitance of the variable capacitor C_(V),thereby changing the gate voltage of the thin film transistor TFT3.After the thin film transistor TFT3 is turned on, signals correspondingto trails of the touch command can be transmitted to a central processor(not shown in FIG. 2) via the turned-on thin film transistor TFT3 andthe sensor signal line Psd for identifying the touch command. In theprior art LCD device 20, the capacitance of the variable capacitor C_(V)depends on the amount of force from the user when entering the touchcommand. Since the gate voltage of the thin film transistor TFT3 cannotbe controlled directly, residual charges may blur the signalscorresponding to the touch command, and the ability to identifydifferent touch commands accurately is thus influenced.

Reference is made to FIG. 3 for a diagram of an LCD device 30 disclosedin U.S. Patent Publication No. US2004/0169625. The LCD device 30includes a first substrate 112, a first electrode 114, a liquid crystallayer 115, a second electrode 116, and a second substrate 118. Thesecond electrode 116 is disposed on the second substrate 118 andincludes a plurality of pixels PX. A plurality of photo diodes PD arealso disposed on the second substrate 118 for sensing input signalsgiven by a user using a light source 150 (such as an optical pen).Optical signals detected by the photo diodes PD can then be transmittedto a central processor (not shown in FIG. 3) for identifying commandsgiven by the user using the light source 150. The prior art LCD device30 can detect input signals from external light source using the photodiodes PD, but is unable to identify input signals corresponding totouch commands.

SUMMARY OF THE INVENTION

The present invention provides an LCD panel comprising a firstsubstrate; a second substrate in parallel with the first substrate andfacing the first substrate; a first electrode disposed on the firstsubstrate; a first isolating layer disposed on the first electrode; asecond electrode disposed on the second substrate and including a firstregion and a second region; a third electrode disposed on the secondsubstrate and including a third region and a fourth region, wherein thesecond region of the second electrode and the third region of the thirdelectrode is separated by a gap; a second isolating layer disposed onthe first region of the second electrode and on the fourth region of thethird electrode; and a conductor disposed on the first isolating layerat a region corresponding to the gap.

The present invention also provides an LCD panel comprising a firstsubstrate; a second substrate in parallel with the first substrate andfacing the first substrate; a first electrode disposed on the firstsubstrate; a conductor disposed on the first electrode; a firstisolating layer disposed on the first electrode at a region excludingwhere the conductor is disposed; a second electrode disposed on thesecond substrate at a region corresponding to the conductor andincluding a first region and a second region, wherein the conductor isin contact with the first region of the second electrode when the firstand second substrates are moved towards each other due to an appliedforce; and a second isolating layer disposed on the second region of thesecond electrode.

The present invention also provides an LCD panel which comprises a firstsubstrate; a second substrate in parallel with the first substrate andfacing the first substrate; a first electrode disposed on the firstsubstrate; a conductor disposed on the first electrode and having aprotrusive structure; a first isolating layer disposed on the firstelectrode at a region excluding the protrusive structure; a secondelectrode disposed on the second substrate at a region corresponding tothe protrusive structure of the conductor and including a first regionand a second region, wherein the protrusive structure of the conductoris in contact with the first region of the second electrode when thefirst and second substrates are moved towards each other due to anapplied force; and a second isolating layer disposed on the secondregion of the second electrode.

The present invention also provides an LCD device comprising an LCDpanel and a signal processing circuit. The LCD panel comprises aplurality of data lines for transmitting data signals corresponding todisplay images; a plurality of gate lines for transmitting scan signals;a first sensor signal line coupled to a first bias voltage; a secondsensor signal line coupled to a second bias voltage; a display unitcoupled to a corresponding data line and a corresponding gate line fordisplaying images based on scan signals and data signals respectivelyreceived from the corresponding gate line and the corresponding dataline; and a detecting unit coupled to the second sensor signal line,wherein the detecting unit is electrically connected to the first sensorsignal line or electrically isolated from the first sensor signal linebased on a touch command, The signal processing circuit is coupled tothe second sensor signal line for outputting corresponding outputsignals when output signals of the second sensor signal line vary.

The present invention also provides an LCD device comprising an LCDpanel and a signal processing circuit. The LCD panel comprises aplurality of data lines for transmitting data signals corresponding todisplay images; a plurality of gate lines for transmitting scan signals;a sensor signal line; a display unit coupled to a corresponding dataline and a corresponding gate line for displaying images based on scansignals and data signals respectively received from the correspondinggate line and the corresponding data line; and a detecting unit coupledto the sensor signal line based on a touch command. The signalprocessing circuit is coupled to the sensor signal line for outputtingcorresponding output signals when output signals of the sensor signalline vary.

These and other objectives of the present invention will become apparentto those of ordinary skill in the art after reading the followingdetailed description with respect to the preferred embodiments that areillustrated in the various figures and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram of a prior art LCD device.

FIG. 2 is a diagram of another prior art LCD device.

FIG. 3 is a diagram of another prior art LCD device.

FIG. 4 is a cross-sectional diagram of an LCD device according to afirst embodiment of the present invention when not receiving touchcommands.

FIG. 5 is a cross-sectional diagram of an LCD device according to thefirst embodiment of the present invention when receiving touch commands.

FIG. 6 is an equivalent circuit diagram of the LCD device in FIG. 4.

FIG. 7 is an equivalent circuit diagram of the LCD device in FIG. 5.

FIG. 8 is a cross-sectional diagram of an LCD device according to asecond embodiment of the present invention when not receiving touchcommands.

FIG. 9 is a cross-sectional diagram of an LCD device according to thesecond embodiment of the present invention when receiving touchcommands.

FIG. 10 is a cross-sectional diagram of an LCD device according to athird embodiment of the present invention when not receiving touchcommands.

FIG. 11 is a cross-sectional diagram of an LCD device according to thethird embodiment of the present invention when receiving touch commands.

FIG. 12 is a cross-sectional diagram of an LCD device according to afourth embodiment of the present invention when not receiving touchcommands.

FIG. 13 is a cross-sectional diagram of an LCD device according to thefourth embodiment of the present invention when receiving touchcommands.

FIG. 14 is a cross-sectional diagram of an LCD device according to afifth embodiment of the present invention when not receiving touchcommands.

FIG. 15 is a cross-sectional diagram of an LCD device according to thefifth embodiment of the present invention when receiving touch commands.

FIG. 16 is an equivalent circuit diagram of the LCD devices in FIGS. 10,12 and 14.

FIG. 17 is an equivalent circuit diagram of the LCD devices in FIGS. 11,13 and 15.

FIG. 18 is a cross-sectional diagram of an LCD device according to asixth embodiment of the present invention when not receiving touchcommands.

FIG. 19 is a cross-sectional diagram of an LCD device according to thesixth embodiment of the present invention when receiving touch commands.

FIG. 20 is an equivalent circuit diagram of the LCD device in FIG. 18.

FIG. 21 is an equivalent circuit diagram of the LCD device in FIG. 19.

DETAILED DESCRIPTION

References are made to FIGS. 4 and 5. FIG. 4 is a cross-sectionaldiagram illustrating an LCD device 100 according to a first embodimentof the present invention when not receiving touch commands. FIG. 5 is across-sectional diagram illustrating the LCD device 100 when receivingtouch commands. The LCD device 100 includes a first substrate 11, asecond substrate 21, a first isolating layer 31, a second isolatinglayer 41, a first electrode 51, a second electrode 61, a third electrode71, a conductor 81, and a liquid crystal layer 91. The liquid crystallayer 91, disposed between the first substrate 11 and the secondsubstrate 21, can provide incident light with various degrees oftransmission and refraction by rotating liquid crystal molecules inaccordance with applied voltages, thereby displaying images of differentgray scales. The first electrode 51, disposed on the first substrate 11,can be used as a common electrode capable of receiving the commonvoltage required for operating the LCD device 100. The conductor 81 andthe first electrode 51 are electrically isolated from each other due tothe first isolating layer 31 disposed between the conductor 81 and thefirst electrode 51. The second electrode 61 and the third electrode 71,both disposed on the second substrate 21, are not in contact with eachother and are separated by a gap. The center of the gap corresponds tothe center of the conductor 81 disposed on the first substrate 11. Thesecond isolating layer 41 is disposed on predetermined regions of thesecond electrode 61 and the third electrode 71, and on the secondsubstrate 21 at a region corresponding to the gap. Near the gap, thesecond electrode 61 and the third electrode 71 include exposed regionswhere the second isolating layer 41 is not disposed. In other words, thepredetermined region of the second electrode 61 and the liquid crystallayer 91 are separated by the second isolating layer 41, while theexposed region of the second electrode 61 is in direct contact with theliquid crystal layer 91. Similarly, the predetermined region of thethird electrode 71 and the liquid crystal layer 91 are separated by thesecond isolating layer 41, while the exposed region of the thirdelectrode 71 is in direct contact with the liquid crystal layer 91. Theconductor 81 of the LCD device 100 can include a ball-shaped conductorcomposed of gold (Ag) or copper (Au), as well as conductors of variousshapes and composed of other conductive materials. The first electrode51, the second electrode 61 and the third electrode 71 can includeindium tin oxide (ITO) or other types of conductive materials.

When no touch command is applied for giving instructions or enteringdata, the second electrode 61 and the third electrode 71 of the LCDdevice 100 are electrically isolated from each other, as illustrated inFIG. 4. When the user gives instructions or enters data with a touchcommand, a force is applied to the first substrate 11. The distancebetween the first substrate 11 and the second substrate 21 is graduallyshortened until the conductor 81 is in contact with the exposed regionsof the second electrode 61 and the third electrode 71 simultaneously.Therefore, the second electrode 61 and the third electrode 71 of the LCDdevice 100 are electrically connected to each other via the conductor81, as illustrated in FIG. 5.

References are made to FIGS. 6 and 7. FIG. 6 is an equivalent circuitdiagram of the LCD device 100 according to the first embodiment of thepresent invention when not receiving touch commands (corresponding toFIG. 4). FIG. 5 is an equivalent circuit diagram of the LCD device 100when receiving touch commands (corresponding to FIG. 5). A pixel PX ofthe LCD device 100 is used for illustrating the present invention inFIGS. 6 and 7. The pixel PX includes a display unit DC and a detectingunit DC. The display unit DC, coupled to a corresponding data line DLand a corresponding gate line GL_(i), includes a thin film transistorswitch TFT1, a liquid crystal capacitor C_(LC) and a storage capacitorC_(ST1). The detecting unit SC, coupled to corresponding sensor signallines SL_(i) and SL_(o), includes a thin film transistor switch TFT2 anda storage capacitor C_(ST2). A node A corresponds to the exposed regionof the second electrode 61, and a node B corresponds to the exposedregion of the third electrode 71. In the LCD device 100, the sensorsignal line SL is coupled to a voltage Vi, and the sensor signal lineSL_(o) is coupled to a voltage Vref. The LCD device illustrated in FIGS.6 and 7 further includes a signal processing circuit 50 such as anintegrating circuit. For example, the signal processing circuit 50,including devices such as an operational amplifier OP, a capacitor C, areset switch SW, and an analog-to-digital converter ADC, can generate anoutput voltage Vout based on the voltages Vo and Vref.

When no touch command is applied, the second electrode 61 and the thirdelectrode 71 are electrically isolated (as illustrated in FIG. 4), andthe corresponding equivalent circuit diagram of the LCD device 100 isillustrated in FIG. 6. Since the node A and the node B areopen-circuited, the voltage Vi cannot be transmitted to the storagecapacitor C_(ST2). When the thin film transistor switch TFT2 is turnedon, the level of the storage capacitor C_(ST2) is kept at the voltagelevel of Vref. Under these circumstances, signals received at the twoinput ends of the operational amplifier OP have the same voltage level(Vo=Vref), and the signal processing 50 will not detect any variation incurrent. When a touch command is applied, the second electrode 61 andthe third electrode 71 are electrically connected to each other via theconductor 81 (as illustrated in FIG. 5), and the correspondingequivalent circuit diagram of the LCD device 100 is illustrated in FIG.7. Since the node A and the node B are short-circuited, the voltage Vican be transmitted to the storage capacitor C_(ST2), thereby changingthe level of the storage capacitor C_(ST2). When the thin filmtransistor switch TFT2 is turned on, the level of the storage capacitorC_(ST2) also varies. Under these circumstances, signals received at thetwo input ends of the operational amplifier OP have different voltagelevels (Vo≠Vref), and the signal processing circuit 50 can measurecurrent variations due to the touch command based on the voltagedifference.

References are made to FIGS. 8 and 9. FIG. 8 is a cross-sectionaldiagram illustrating an LCD device 200 according to a second embodimentof the present invention when not receiving touch commands. FIG. 9 is across-sectional diagram illustrating the LCD device 200 when receivingtouch commands. The LCD device 200 includes a first substrate 12, asecond substrate 22, a first isolating layer 32, a second isolatinglayer 42, a first electrode 52, a second electrode 62, a third electrode72, a protrusion PS, and a liquid crystal layer 92. The liquid crystallayer 92, disposed between the first substrate 12 and the secondsubstrate 22, can provide incident light with various degrees oftransmission and refraction by rotating liquid crystal molecules inaccordance with applied voltages, thereby displaying images of differentgray scales. The first electrode 52, disposed on the first substrate 12,can be used as a common electrode capable of receiving the commonvoltage required for operating the LCD device 200. The protrusion PS andthe first electrode 52 are electrically isolated from each other due tothe first isolating layer 32 disposed between the protrusion PS and thefirst electrode 52. The protrusion PS includes light-blocking materialsand can prevent light leak between the pixels of the LCD device 200. Inthe second embodiment of the present invention, a conductor 82 isfurther disposed on the protrusion PS. The second electrode 62 and thethird electrode 72, both disposed on the second substrate 22, are not incontact with each other and are separated by a gap. The center of thegap corresponds to the center of the conductor 82 disposed on theprotrusion PS. The second isolating layer 42 is disposed onpredetermined regions of the second electrode 62 and the third electrode72, and on the second substrate 22 at a region corresponding to the gap.Near the gap, the second electrode 62 and the third electrode 72 includeexposed regions where the second isolating layer 42 is not disposed. Inother words, the predetermined region of the second electrode 62 and theliquid crystal 92 are separated by the second isolating layer 42, whilethe exposed region of the second electrode 62 is in direct contact withthe liquid crystal layer 92. Similarly, the predetermined region of thethird electrode 72 and the liquid crystal 92 are separated by the secondisolating layer 42, while the exposed region of the third electrode 72is in direct contact with the liquid crystal layer 92.

When no touch command is applied for giving instructions or enteringdata, the second electrode 62 and the third electrode 72 of the LCDdevice 200 are electrically isolated from each other, as illustrated inFIG. 8. In this case, the equivalent circuit diagram of the LCD device200 is also illustrated in FIG. 6. When the user gives instructions orenters data with a touch command, a force is applied to the firstsubstrate 12. The distance between the first substrate 12 and the secondsubstrate 22 is gradually shortened until the conductor 82 on theprotrusion PS is in contact with the exposed regions of the secondelectrode 62 and the third electrode 72 simultaneously. Therefore, thesecond electrode 62 and the third electrode 72 of the LCD device 200 areelectrically connected to each other via the conductor 82, asillustrated in FIG. 9. In this case, the equivalent circuit diagram ofthe LCD device 200 is illustrated in FIG. 7.

References are made to FIGS. 10 and 11. FIG. 10 is a cross-sectionaldiagram illustrating an LCD device 300 according to a third embodimentof the present invention without receiving touch commands. FIG. 11 is across-sectional diagram illustrating the LCD device 300 when receivingtouch commands. The LCD device 300 includes a first substrate 13, asecond substrate 23, a first isolating layer 33, a second isolatinglayer 43, a first electrode 53, a second electrode 63, a third electrode73, a conductor 83, and a liquid crystal layer 93. In the LCD device 100according to the first embodiment of the present invention, as shown inFIG. 4, the first isolating layer 31 is disposed between the conductor81 and the first electrode 51. Thus, the conductor 81 and the firstelectrode 51 are electrically isolated. In the LCD device 300 accordingto the third embodiment of the present invention, as shown in FIG. 10,the conductor 83 is disposed on the first electrode 53 directly. Thus,the voltage levels of the conductor 81 and the first electrode 53 areboth equal to the common voltage. Also, the second electrode 63, havinga contact surface, is disposed on the second substrate 23 at a regioncorresponding to the conductor 83. The third electrode 73, also disposedon the second substrate 22, is not in contact with the second electrode63. The first isolating layer 33 is disposed on the first electrode 53at regions where the conductor 83 is not disposed. The second isolatinglayer 43 is disposed on the third electrode 73, as well as on the secondelectrode 63 at regions excluding the contact surface. The conductor 83of the LCD device 300 can include a ball-shaped conductor composed ofgold or copper, as well as conductors of various shapes and composed ofother conductive materials. The first electrode 53, the second electrode63 and the third electrode 73 can include ITO or other types ofconductive materials.

When no touch command is applied for giving instructions or enteringdata, the conductor 83 of the LCD device 300 and the second electrode 63are electrically isolated from each other, as illustrated in FIG. 10.When the user gives instructions or enters data with a touch command, aforce is applied to the first substrate 13. The distance between thefirst substrate 13 and the second substrate 23 is gradually shorteneduntil the conductor 83 is in contact with the contact surface of thesecond electrode 63. Therefore, the first electrode 53 and the secondelectrode 63 are electrically connected to each other via the conductor83, as illustrated in FIG. 11.

References are made to FIGS. 12 and 13. FIG. 12 is a cross-sectionaldiagram illustrating an LCD device 400 according to a fourth embodimentof the present invention when not receiving touch commands. FIG. 13 is across-sectional diagram illustrating the LCD device 400 when receivingtouch commands. The LCD device 400 includes a first substrate 14, asecond substrate 24, a first isolating layer 34, a second isolatinglayer 44, a first electrode 54, a second electrode 64, a third electrode74, and a liquid crystal layer 94. The LCD devices 300 and 400 havesimilar structures. In the LCD device 300 according to the thirdembodiment of the present invention, the conductor 83 is furtherdisposed on the first electrode 53. In the LCD device 400 according tothe fourth embodiment of the present invention, the first electrode 54includes a protrusive structure 84. In the fourth embodiment of thepresent invention, the protrusive structure 84 can be formed by etchingthe first electrode 54. Next, the first isolating layer 34 is disposedon the first electrode 54, followed by removing the first isolatinglayer 34 formed on the protrusive structure 84. Therefore, theprotrusive structure 84 can be in direct contact with the liquid crystallayer 94.

When no touch command is applied for giving instructions or enteringdata, the first electrode 54 and the second electrode 64 of the LCDdevice 400 are electrically isolated from each other, as illustrated inFIG. 12. When the user gives instructions or enters data with a touchcommand, a force is applied to the first substrate 14. The distancebetween the first substrate 14 and the second substrate 24 is graduallyshortened until the protrusive structure 84 of the first electrode 54 isin contact with the contact surface of the second electrode 64.Therefore, the first electrode 54 and the second electrode 64 areelectrically connected to each other, as illustrated in FIG. 13.

References are made to FIGS. 14 and 15. FIG. 14 is a cross-sectionaldiagram illustrating an LCD device 500 according to a fifth embodimentof the present invention when not receiving touch commands. FIG. 15 is across-sectional diagram illustrating the LCD device 500 when receivingtouch commands. The LCD device 500 includes a first substrate 15, asecond substrate 25, a first isolating layer 35, a second isolatinglayer 45, a first electrode 55, a second electrode 65, a third electrode75, and a liquid crystal layer 95. The LCD devices 400 and 500 havesimilar structures. In the LCD device 400 according to the fourthembodiment of the present invention, the first electrode 54 includes aprotrusive structure 84. In the LCD device 500 according to the fifthembodiment of the present invention, a spacer 5 is used for defining aprotrusive structure 85 of the first electrode 55. In the fifthembodiment of the present invention, the spacer 5 is first disposed on apredetermined location of the first substrate 15 before disposing thefirst electrode 55. Consequently, the first electrode 55 can include theprotrusive structure 85. Next, the first isolating layer 35 is disposedon the first electrode 55, followed by removing the first isolatinglayer 35 formed on the protrusive structure 85. Therefore, theprotrusive structure 85 of the first electrode can be in direct contactwith the liquid crystal layer 95.

When no touch command is applied for giving instructions or enteringdata, the first electrode 55 and the second electrode 65 of the LCDdevice 500 are electrically isolated from each other, as illustrated inFIG. 14. When the user gives instructions or enters data with a touchcommand, a force is applied to the first substrate 15. The distancebetween the first substrate 15 and the second substrate 25 is graduallyshortened until the protrusive structure 85 of the first electrode 55 isin contact with the contact surface of the second electrode 65.Therefore, the first electrode 55 and the second electrode 65 areelectrically connected to each other, as illustrated in FIG. 15.

References are made to FIGS. 16 and 17. FIG. 16 is an equivalent circuitdiagram of the LCD devices according to the third through fifthembodiments of the present invention when not receiving touch commands(corresponding to FIGS. 10, 12 and 14). FIG. 17 is an equivalent circuitdiagram of the LCD devices according to the third through fifthembodiments of the present invention when receiving touch commands(corresponding to FIGS. 11, 13 and 15). A pixel PX of the LCD device isused for illustrating the present invention in FIGS. 16 and 17. Thepixel PX includes a display unit DC and a detecting unit DC. The displayunit DC, coupled to a corresponding data line DL and a correspondinggate line GL_(i), includes a thin film transistor switch TFT1, a liquidcrystal capacitor C_(LC) and a storage capacitor C_(ST1). The detectingunit SC, coupled to a sensor signal lines SL_(o), includes a thin filmtransistor switch TFT2 and a storage capacitor C_(ST2). A node Acorresponds to the conductor 83, the protrusive structure 84 of thefirst electrode 54, or the protrusive structure 85 of the firstelectrode 55. A node B corresponds to the second electrode 63, 64 or 65.The LCD device illustrated in FIGS. 16 and 17 further includes an signalprocessing circuit 50, such as an integrating circuit. The signalprocessing circuit 50, including devices such as an operationalamplifier OP, a capacitor C, a reset switch SW, and an analog-to-digitalconverter ADC, can generate an output voltage Vout based on the voltagesVo and Vref.

When no touch command is applied, the first electrodes 53-55 areelectrically isolated from the second electrodes 63-65 respectively (asillustrated in FIGS. 10, 12 and 14), and the corresponding equivalentcircuit diagram of the LCD devices 300, 400 and 500 is illustrated inFIG. 16. Since the node A and the node B are open-circuited, the commonvoltage V_(com) cannot be transmitted to the storage capacitor C_(ST2).When the thin film transistor switch TFT2 is turned on, the level of thestorage capacitor C_(ST2) is kept at the voltage level of Vref. Underthese circumstances, signals received at the two input ends of theoperational amplifier OP have the same voltage level (Vo=Vref), and thesignal processing circuit 50 will not detect any variation in current.When a touch command is applied, the first electrodes 53-55 areelectrically connected to the second electrodes 63-65 respectively (asillustrated in FIGS. 11, 13 and 15), and the corresponding equivalentcircuit diagram of the LCD devices 300, 400 and 500 is illustrated inFIG. 17. Since the node A and the node B are short-circuited, the commonvoltage V_(com) can be transmitted to the storage capacitor C_(ST2),thereby changing the level of the storage capacitor C_(ST2). When thethin film transistor switch TFT2 is turned on, the level of the storagecapacitor C_(ST2) also varies. Under these circumstances, signalsreceived at the two input ends of the operational amplifier OP havedifferent voltage levels (Vo≠Vref), and the signal processing circuit 50can measure current variations due to the touch command based on thevoltage difference.

References are made to FIGS. 18 and 19. FIG. 19 is a cross-sectionaldiagram illustrating an LCD device 600 according to a sixth embodimentof the present invention when not receiving touch commands. FIG. 19 is across-sectional diagram illustrating the LCD device 600 when receivingtouch commands. The LCD device 600 includes a first substrate 16, asecond substrate 26, a first isolating layer 36, a second isolatinglayer 46, a first electrode 56, a second electrode 66, a third electrode76, a conductor 86, a liquid crystal layer 96, and a bias electrode 6.The LCD devices 300 and 600 have similar structures. In the LCD device300 according to the third embodiment of the present invention, theconductor 83 is disposed on the first electrode 53. In the LCD device600 according to the sixth embodiment of the present invention, theconductor 83 is disposed on the bias electrode 6 capable of receiving abias voltage V_(BIAS) having a voltage level different than that of thecommon voltage. The bias electrode 6 can include ITO or other types ofconductive materials.

When no touch command is applied for giving instructions or enteringdata, the conductor 86 and the second electrode 66 of the LCD device 600are electrically isolated from each other, as illustrated in FIG. 18.When the user gives instructions or enters data with a touch command, aforce is applied to the first substrate 16. The distance between thefirst substrate 16 and the second substrate 26 is gradually shorteneduntil the conductor 86 is in contact with the contact surface of thesecond electrode 66. Therefore, the bias electrode 6 and the secondelectrode 66 are electrically connected to each other, as illustrated inFIG. 19.

References are made to FIGS. 20 and 21. FIG. 20 is an equivalent circuitdiagram of the LCD device 600 according to the sixth embodiment of thepresent invention when not receiving touch commands (corresponding toFIG. 18). FIG. 21 is an equivalent circuit diagram of the LCD device 600when receiving touch commands (corresponding to FIG. 19). A pixel PX ofthe LCD device 600 is used for illustrating the present invention inFIGS. 20 and 21. The pixel PX includes a display unit DC and a detectingunit DC. The display unit DC, coupled to a corresponding data line DLand a corresponding gate line GL_(i), includes a thin film transistorswitch TFT1, a liquid crystal capacitor C_(LC) and a storage capacitorC_(ST1). The detecting unit SC, coupled to a sensor signal line SL_(o),includes a thin film transistor switch TFT2 and a storage capacitorC_(ST2). A node A corresponds to the conductor 86, and a node Bcorresponds to the second electrode 66. The LCD device illustrated inFIGS. 20 and 21 further includes a signal processing circuit 50, such asan integrating circuit. The signal processing circuit 50, includingdevices such as an operational amplifier OP, a capacitor C, a resetswitch SW, and an analog-to-digital converter ADC, can generate anoutput voltage Vout based on the voltages Vo and Vref.

When no touch command is applied, the bias electrode 6 and the secondelectrode 66 are electrically isolated (as illustrated in FIG. 18), andthe corresponding equivalent circuit diagram of the LCD device 600 isillustrated in FIG. 20. Since the node A and the node B areopen-circuited, the voltage V_(BIAS) from the bias electrode 6 cannot betransmitted to the storage capacitor C_(ST2). When the thin filmtransistor switch TFT2 is turned on, the level of the storage capacitorC_(ST2) is kept at the voltage level of Vref. Under these circumstances,signals received at the two input ends of the operational amplifier OPhave the same voltage level (Vo=Vref), and the signal processing circuit50 will not detect any variation in current. When a touch command isapplied, the bias electrode 6 and the second electrode 66 areelectrically connected to each other via the conductor 86 (asillustrated in FIG. 19), and the corresponding equivalent circuitdiagram of the LCD device 600 is illustrated in FIG. 21. Since the nodeA and the node B are short-circuited, the voltage V_(BIAS) from the biaselectrode 6 can be transmitted to the storage capacitor C_(ST2), therebychanging the level of the storage capacitor C_(ST2). When the thin filmtransistor switch TFT2 is turned on, the level of the storage capacitorC_(ST2) also varies. Under these circumstances, signals received at thetwo input ends of the operational amplifier OP have different voltagelevels (Vo≠Vref), and the signal processing circuit 50 can measurecurrent variations due to the touch command based on the voltagedifference.

In the present invention, the LCD device does not require an extra touchpanel for receiving touch commands. Therefore, the present LCD devicecan reduce manufacturing costs and provide higher display quality. Also,the present invention can accurately identify touch commands based onthe conduction between two independent lower electrodes or between anupper electrode and a lower electrode.

Those skilled in the art will readily observe that numerousmodifications and alterations of the device and method may be made whileretaining the teachings of the invention. Accordingly, the abovedisclosure should be construed as limited only by the metes and boundsof the appended claims.

1. A liquid crystal display (LCD) panel comprising: a first substrate; asecond substrate, disposed in parallel with the first substrate, facingthe first substrate; a first electrode disposed on the first substrate;a first isolating layer disposed on the first electrode; a secondelectrode disposed on the second substrate and including a first regionand a second region; a third electrode disposed on the second substrate,including a third region and a fourth region, wherein the second regionof the second electrode and the third region of the third electrode areseparated by a gap; a second isolating layer disposed on the firstregion of the second electrode and on the fourth region of the thirdelectrode without overlaying the second region of the second electrodeand the third region of the third electrode; and a conductor disposed onthe first isolating layer at a region corresponding to the gap so as tocontact the second region of the second electrode and the third regionof the third electrode in response to a touch command.
 2. The LCD panelof claim 1 further comprising: a spacer disposed between the conductorand the first isolating layer.
 3. The LCD panel of claim 1 furthercomprising: a third isolating layer disposed on the second substrate ata region corresponding to the gap.
 4. The LCD panel of claim 3 whereinat least one of the first, second and third isolating layers comprisespolyimide (PI).
 5. The LCD panel of claim 1 wherein at least one of thefirst, second and third electrodes comprises indium tin oxide (ITO). 6.The LCD panel of claim 1 wherein the conductor comprises copper, gold,or conductive materials.
 7. The LCD panel of claim 1 wherein theconductor is ball-shaped.
 8. The LCD panel of claim 1 furthercomprising: a liquid crystal layer interposed between the first andsecond substrates.